Method of applying mulch



July 11, 1967 R. L.. PERM ETAL.

METHOD 0F APPLYING MULCH '2 Sheets-Sheet l Filed Dec. 29, 1965 HlllllllFIG.2

SMHM Y RMWO mFmM m NL En. R Eovmwv T vnr NAEM T IHNAW, A www E RSC Y BJuly 11, 1967 R. FERM ETAL METHOD OF APPLYING MULCH 2 Sheets-Sheet FiledDec. 29, 1965 coNveRToR I l l To GENERATOR m M M Swmm Y 0R RE/ a E TEOFMM N T SE. ,A N E G N/ Msdf O ED E VRyLna T NAERvf T IHN A CMM msc Y B4 G F /5 H United States Patent O 3,330,070 IVIETHUD F APPLYING MULCHRichard L. Ferm, El Cerrito, Sidney V. Smith, Yuba City, and Charles E.Moran, Richmond, Calif., assignors to Chevron Research Company, SanFrancisco, Calif., a corporation of Delaware Filed Dec. 29, 1965, Ser.No. 517,314 3 Claims. (Cl. 47-9) This application is yacontinuation-impart of application Ser. No. 294,897, iiled luly 15,1963, now abandoned.

This invention relates to improved agricultural methods and, moreparticularly, this invention relates to methods for selectively applyingfluid mulch substances, such as petroleum based emulsions, to the soilto prevent crusting of the soil and to promote germination of seeds inagricultural practice.

Soil crusting is a widely occurring problem in agriculture and a seriousobstacle to plant emergence and development. Formation of a crust aftera field has been seeded interferes with and even precludes emergence andnormal healthy growth of the seedlings. Germinated, sprouted seedlings-are often unable to break through the crust and uneven and weak cropstands result. When nneven emergence of seedlings, and as a consequencenonuniform development and ripening, occurs, in the case of lettuce forinstance, hand labor must be sent out to harvest the crop because amachine would be nonselective between the ripened and non-ripenedportion. Obviously, this increases operating costs of producing thecrop.

The problem of soil crusting has been recognized and many solutions havebeen advanced to solve it. One solution has been the application of amulching liuid to the soil after seeding. Heretofore, the mulch oranticrusting agent has been uniformly applied to the field, eitherentirely or in regularly spaced bands running the length of the seedbed. The application of a mulching material to the lield often overcomesthe soil crusting problem. However, the above methods of applying themulching material, which methods were heretofore thought necessary toobtain good results, resulted in waste of a large portion of themulching material. Further, in the case of certain agricultural productssuch as lettuce, etc., Where the common practice is to plant acontinuous row of seeds, allow them to germinate and emerge, and then tothin the seedlings out by hand so that plants remain only at selectedintervals, the previously practical methods of applying a mulchingmaterial over the entire row of seeds did nothing to solve the problemof later thinning the crop. Further problems that are associated withapplying the mulching agent in the above manner include the largequantity of mulch needed to cover the field and the resulting highWeight of the equipment for applying it.

It is a particular object of this invention to provide methods forapplying petroleum based emulsions to the soil of a seed bed in spotshaving limited areal coverage and spaced apart at predeterminableselected intervals.

Briey, the present invention comprises the steps of establishing amovable reservoir of a petroleum based emulsion having a viscositywithin a preselected range, moving the reservoir over a soil surfacecontaining planted seeds, applying a predeterminable pressure on theemulsion in the reservoir, owing at least a portion of the emulsionIagent to a position above the soil and then di- 3,339,070 Patented July1l, 1967 recting a limited amount of the emulsion at the soil to producea spot or an impact `area of the emulsion on the seeded soil having agenerally circular pattern of relatively small diameter and movin-g saidreservoir along the seed row while periodically directing limitedquantities of emulsion at lthe soil to provide mulched spots of limitedareal coverage at intervals over the seed bed.

Further objects and advantages ofthe invention will become apparent fromthe following detailed description read in light of the accompanyingdrawings which are a part of this specification and in which:

FIGURE l is a view illustrating an embodiment of apparatus useful inperforming the method of the present invention;

FIGURE 2 is a sectional view of a form of nozzle useful in the presentinvention;

FIGURE 3 is -a diagrammatic view and illustrates apparatus assembled inaccordance With the invention;

FIGURE 4 is a diagrammatic View and illustrates apparatus -assembled inaccordance with an alternative ern- Vbodirnent of the invention.

In FIGURE 1 a planted field is Igenerally represented by the numeral 20.Seeds have been sown or planted in rows 22. For example, lettuce seedsare commonly planted by a mechanical seeder which deposits a continuousstream ofrseeds in proper position along a row such as row 22. Theplanted rows 22 are spaced apart by furrows 24. The arrangement of thefield in FIGURE l is general and similar arrangements are =used withmany crops.

A tractor, represented generally by numeral 26, is shown. The rearWheels 2S and 30 of the tractor run in the furrows as do the frontwheels 32. The tractor 26 is a suitable movable frame from moving theapparatus of the present invention over the field 20. Reservoir means,such as tank 34, are mounted on and carried by the tractor 26. Thereservoir means 34 should provide for at least 20 gallons of liquidstorage capacity and preferably 40 to 50 gallons of liquid storagecapacity. The reservoir means is constructed in a manner to withstand atleast 50 p.s.i. A means to increase the pressure on the contents of thereservoir means is also provided. For example, a compressor 36 and drivemotor 37 are mounted on the tractor 26 on platform 38. An air supplyline 39 carries compressed air from the compressor through valve 40 andpressure gauge 41 to the reservoir means 34. In this manner the pressureon the reservoir may be maintained at a desired level. A blowdown line42 is provided with a manually operated Valve 43 to release the pressureon uid in the reservoir 34 when desirable.

A conduit 44 extends out of the reservoir 34 for owing uid therefrom. Avalve 45 is provided on the conduit 44 within easy reach of the operatorof the tractor. Conduit 44, which may be divided into two or moreconduits such as 53 and 54 provides a path for flowing the emulsion fromthe reservoir 34 to a position as indicated by numerals 46 and 52directly above the planted field 20.

A support member 51 extends downwardly from the tractor 26. The supportmember is rigidly connectable on the tractor. A pair of suitable valves47 and 48, which may be solenoid valves for example, are affixed to theframe 51. The valves 47 and 48 are connected on conduits 53 and 54 tocontrol ow therethrough. Nozzles 49 and 50 are connected to the valves47 and 48, respectively, to receive any flow passing therethrough.Thenozzlcs 49 3 and 50 are positioned to direct a spray, as indicated by55 and 56, at the earth. The spray leaving the nozzle is radiallyexpanding and forms on striking the earth a generally circular patternhaving a substantially constant density. f

Actuating means are provided to actuate the valves 47 ence to VFIGURE 3.The actuating'means in box 60 isY supplied with current by means otleads 61 and 62 ex- --tending from the generator electric cables 65 and66 carry the current from box 60 63 of the tractor. Suitable to thesolenoid valves 47 and 48 to operate the valves. A manual switch (notshown) may be incorporated into the electrical system at Va suitablelocation for manual cut olfV of the system if desired.

A regular pattern of spot applications of the emulsion is made. Theactuating device periodically opens the valves for a short time periodtoY cause the emulsion to be `sprayed on the ground in a pattern'havingsubstantially constant density. It has been found that the applicationof the emulsion to the soil surface need not be continuous to beeffective. In fact it has been found that spot application having agenerally circular pattern with a diameter as small as 2"V givessatisfactory results when spaced Yat the desired plant spacing along therow. According to the present invention then the tractor is moved acrossthe eld in a manner to align the nozzles with the seeded rows and theactuating means is set with a predeterminable program to cause a sprayof uniform-density to jet from the nozzles at periodic intervals alongthe seed rows to provide spots of emulsion at selected intervals alongthe seed row. Y Y

A sectional view of a preferred form of nozzle, such as `for examplenozzle 49, is shown in FIGURE 2. As'there shown, the nozzle comprises anupper bodysection 70 and a lower body section 71. A ow path 72 isprovided through the interior of the body sections. The flow path has anorifice 73 which causes the emulsion flowing through the nozzle t-o bejetted therefrom in an expanding stream. A pair of circular discs 75and-76 are arranged in the ow path 72 to impart a swirling motion to theemulsion passing through and to thus provide a stream having asubstantially constant density. The nozzle lhas a delivery range frombetween 1.0 to 2.0 gallons per minute of a fluid having a viscosity ofto 200 SSF at 40 p.s.i. pressure.

With reference to FIGURE 3, the preferredV embodiment of apparatususeful in the present invention is ldiagrammatically illustrated. Thereservoir means 101 is supvalve 110. The valve remains opened while therod is in the notch. As the wheel 118 turns, the rod 117 is depressed tocause the switch to open and thus close'the valve. In this manner a spotof emulsion is sprayedat periodic intervals through nozzle 122. Thus thepulsating apparatus of the invention provides spot application ofemulsion at selected intervals along the seed row.

An alternative arrangement of apparatus for periodically applying a spotof emulsion to the soil is diagrammatically shown in FIGURE 4.'Ayreservoir 101 of emulsion 105 is maintained at a suitable pressure bycompressor 104. A solenoid valve 110 and nozzle 122 are connected in anappropriate location and communicate'with plied with a suitable inletconduit 102 and an outlet con- Y duit 103. A compressor 104 is providedto apply pressure to the emulsion 105 contained in reservoir 101.Suitable valves 106, 107 and 108 are connected, respectively, to theinlet conduit 102, the blowofr line, and the outlet conduit 103. Anormally closed solenoid valve 110 is connected on conduit 103. Thevalve isopened when coil 112 vis energized to cause core 111 to move outof and to thus open the valve. The coil is connected in series by leads116 and 115 and is periodically electrically-excited by suitable meanssuch as the equipment shown inside of box 60. The electrical leads 115and 116 are connected to a suitable source of current such as agenerator. A normally open switch 114 is connected into conduit 116. Theswitch is open so long as spring-loaded push rod 117 is depressed by anotched wheel 118. The notched wheel 118.is rotated by shaft 119 drivenat a constant speed by motor 1270. As the push rod of the normally openswitch 114 extends into each notch 121 of wheel 118, the switch isclosed energizing the coil 112 to open the solenoid has been found thatthe nozzle should be between about the outlet conduit from reservoir101. The Vsolenoid valve 10 is normally in a closed positionto preventflow through nozzle 122. The solenoid valve is Iopened by excitation ofcoil 112. The coil is excited periodically -byran actuating meanscomprising ground wheel 126, drive shaft p 127, notched wheel 125, andswitch 114. The switch is in a closed position when the switch button isextended into a notch on wheel 125. When the button is depressed by therim of the wheel 125,- the switch opens to close the solenoid valve 110.

In this regard the sizeof and theV spacing of the notches on the notchedor timing wheel control the size of the spot and the location of thespots. It will be apparent that sinceV different crops require spotapplications on different centers, it is within the slrill of the art toprepare a timing wheel of the proper diameter and notches of propersize.

In order to effectively prevent crusting of the soil and to promote seedgermination and seedling emergence, the emulsion is applied to tthe soilin a particular manner.

Thus it has been found that the emulsion to be sprayed onV the soilrinaccordance with the present invention should have a viscosity of betweenabout 10 and 200 SSF at 77 F. A particular mulching composition "that isuseful'in accordance with this invention is fully described in copendingapplication Ser. No. 295,230, tiled on July 15, 1963, by Richard L. Fermand Charles E. Moran, and owned by a common assignee. The'emulsion asthere described is mixed Vwith water in an appropriate manner to providea mulching huid-'having a viscosity within a range of 10 to 200 SSF at77 F.

The nozzle used to jet the emulsion at the soil emits the emulsion in atine spray without breaking theemulsion. The density of the phases `inthe expandingspray is substantially contant to provide uniform emulsionapplication in the impact area. In this regard it has been discoveredthat beneficial results are obtainedwith relatively small areas ofemulsion application. Areas or spots Vof emulsion application about 2 to3" in diameter have given excellent results. It has been found that thedensity of an emulsion having a viscosity of l0 to 200 vSSF at 77or F.when applied in'this manner should be in the range of .05 gallon persquare yard to l.2 gallon per square yard of application. The bestresults are obtained in this invention:

by using an emulsion for spraying, which emulsion has a viscosity ofbetween l5k and 40 SSF at 77 F.

The manner in which the spray is directed at the earths surface isimportant to the successful application of the emulsion in accordancewith this invention. The spray must not only be of a critical density asindicated above, it must also be directed at the ground in a particularmanner. The nozzle through which the mulch is jetted must 4" and 8 andpreferably about 6v above the soil surface on which the emulsion isapplied. The emulsion is sprayed through a nozzle having a delivery rateof between 1 to 2 gallons per minute of a fluid having a viscosity of l0to 200 SSF at 40 p.s.i. The pressure on the emulsion when it isdelivered is adjusted to a value between about 30 and 60 p.s.i.Pressurcs greater than 60 p.s.i. cause the sprayed emulsion to erode thesoil when striking. On the other hand the spray of emulsion is notsatisfactorily atomized when the pressure on the reservoir issubstantially less than 30 p.s.i. Thus the proper application of theemulsion in spots in accordance with the invention is dependent in theserespects on the pressure on the reservoir.

The method of spot applying emulsion mulch in accordance with thepresent invention is useful with a variety of plants. Suitable plantsinclu-de lettuce, sugar beets, cotton, melons, and other plants whichare planted as seeds in a row. Application of the emulsion in spots hasbeen found to result in excellent plant emergence in the spottedportions of the seed bed. Thus waste of emulsion is prevented. Further,applying the emulsion in periodic spots helps to aid in thinning thecrop. Thus the spots are applied at various intervals over the seed row.For example, a desirable interval (center to center) of spots applied tolettuce is about l2 to 14 inches. Following are typical examples whichillustrate the improvement in crop production in accordance with thepresent method:

Example 1 Oronite Polybutene No. 32 59.6 Oronite NI-W 5.4 Fresh water35.0

This concentrated emulsion was subsequently diluted in a. ratio of 1:1with water to provide a suitable emulsion for application in accordancewith the invention. This emulsion had a viscosity of approximately 30 to40 SSF at 77 F. The Oronite Polybutene No. 32 is a liquid polymericmaterial produced in the plants of Chevron Chemical Company, OroniteDivision. Various types of this material are sold under registeredtrademark designations 'of Oronite Polybutenes Nos. 24, 32, 64, 122V and128. These materials are suitable for'the preparation of emulsions foruse in this invention. The Oronite NI-W is an ether of alkyl phenoluseful as a liquid dispersant. It is sold under the trademark DispersantNI-W by Chevron Chemical Company, Oronite Division, of San Francisco,Calif. In this material the alkyl chain contains an average of 12 to 14carbon atoms, the number of ethylene oxide units to impart watersolubility being in the range from 8 to 12. The formulation andcomposition of the emulsion is fully described in copending applicationSer. No. 295,230 cited above. Application was made in spotsapproximately 2 inches in diameter at l2inch centers over the seed rows.The location of this trial was in the vicinity of Soledad, Calif. Thefield consisted of the soil type designated as Salinas clay. Irrigationwas accomplished by sprinkling approximately 2 to 3 inches of water tothe soil.

Approximately 21 days elapsed from the time of application of theemulsion until the observation of the test results. At the time ofobservation, it was noted that the untreated portion of the eld hadcrusted badly, requiring the grower to roll the beds in order to breakthe crust.

The spots which were treated with the polybutene emulsion did not crust.A healthy seedling Vemerged in every spot thus demonstrating theeffectiveness of the emulsion or a mulch when applied in this manner.The breakthrough of seedlings in the untreated portion was spotty anderratic. Further, greater maturity was clearly apparent in the plants inthe treated spots.

Example II water in a 1:1 ratio to give an emulsion having a viscosityof between 30 and 40 SSP at 77 F. The iield size was somewhat greaterthan 30 acres. 'Ihe treated rows were approximately 500 feet long with72 inches between rows. Two-inch spot applications of the emulsion wereapplied on approximately 72-inch centers. The trial was located nearMendota, Calif., and was on a silty, clay loam.

Approximately 20 days after treatment, during which time the field hadreceived intermittent rains, it was noted that emergence of seedlingshad occurred through each spot in the spot-treated rows. On the otherhand emergence was very erratic in the untreated areas. Thus theemergence of plants in the treated spots indicates that the emulsionapplied in small diameter spots in accordance with this invention iseffective in preventing crusting and providing for seedling emergencewith a minimum of Wasting of emulsion. Y

Example III In this case, a lS-acre field of broccoli was treated withthe same polybutene emulsion diluted as in the previous examples. Theuntreated rows were about 600 feet long on raised beds, 40 inches oncenters. The emulsion was applied in 2-inch spots on about l2inchcenters in accordance with the method of this invention. The trial waslocated near Salinas, Calif., on silty, clay loam. Irrigation was bysprinkling with about 2 to 3 inches of water which resulted in the usualcrusting problems. About 20 days after the treatment it was observedthat excellent emergence and maturity had been obtained in the treatedarea, but that the rest of the eld had to be rolled in order to allowadequate emergence of the crop.

Example IV The emulsied Polybutene applied in this treatment was thesame as in the foregoing examples. The treatment was the spot method ona l5-acre eld of cauliower, near Salinas, Calif. Spots of emulsion ofapproximately 2 inches in diameter were applied on l2inch centers. Thetreated rows were about 200 feet long on raised beds, 40 inches oncenters. The field was one of silty, cl-ay loam. Again irrigation was bysprinkling with from 2 to 3 inches of water.

About 20days after the treatment, it was observed, as in the Iotherexamples, that the treatment had allowed emergence of the crop withoutresort to rolling and had resulted in a greater number of plantsemerging and in greater maturity.

Example V Additional demonstrations were conducted to show theadvantages of the present invention using an asphalt emulsion.Originally, the asphalt emulsion comprised by weight about 58 percentasphalt, about 40 percent fresh water, about 2 percent Vinsal resin andabout .22 percent sodium hydroxide. Vinsal resin is a pine stump extractmade by the HerculesPowder Company. The Vinsal resin has an acid numberof 94 and a saponiiication number of 165. The molecular Weight of theresin is 470, and the density is 1.218 at 25 C. The CH3O content is5.3.percent. The above asphalt emulsion was diluted with an equal weightof water to make an emulsion suitable for use in the present invention.The iinal emulsion had a viscosity between about 15 to 18 SSF at 77 F.Spots of emulsion of from about 21/2 to 31/2 inches were formed on thesoil in accordance with the present invention. After 16 days soilsamples were taken at depths of from 0 to 1 inch and from 1 to 3 inchesunder the mulched spots and also, for comparison purposes, between thespots in an untreated area. Table 1 below shows the results of thesetests. It is noted that the average moisture of the soil in the spottedarea is significantly higher than the moisture in the untreated areasimmediately adjacent. The moisture content is a means of indicating theimproved soil condition due to the asphalt emulsion. Y

TABLE l Sample Can No.

Net Dry Sample Weight Percent Moisture Avg Check Area 4 1-3" Sample 8Depth 12 Avg In accordance with the method of the invention,there isalso an application wherein the spot application of the emulsion is usedwith a second treatment to assist'in promoting growth of crops atselected intervals and to thus at least partially, if not completely,eliminate the'need for manual thinning ofthe crops. For example, it hasbeen found that if a seeded iield of a crop such as lettuce is treatedwith the emulsion by spot application as described herein and then theentire tield is watered, a crust will form on the untreated, wateredportion of the field. However, no crust will form on the portions of thefield which were spotted with emulsion prior to the watering. The crusthinders or partially impedes emergence and growth 'of thecrustedportion. In the mulched spots, however,

Y which have no crust, seedlings emerge and grow. Thus the need for handthinning iseliminated or at least greatly reduced.

In a further embodiment of the invention the emulsion is applied by thespotting technique to a row of plants which have already emerged'and aregrowing. Thus in the case of lettuce, for example, where a crowded rowof seedlings emerge and it is desired t=o thin out'the row and haveplants mature at selected intervals, the emulsionY would be spotted onthe lettuce at the desired intervals. A substance which normally killsthe lettuce but which does not aiect the mulched portion of the lettuceis then applied to the whole eld. The unmulched lettuce will be killedwhile the mulched portion will survive and grow. If, for example, it isdesired to automatically thin the lettuce iield 'of EX-amplel above, themulching treatment using the petroleum based emulsion is first doneafter the seedlings emerge. Then the entire iield is sprayed with aYmaterial such as oil which will kill the seedlings in the untreatedareas. Materials other than oil Whichvwill serve the same or similarpurpose include various herbicides.

It is apparent that modifications other than those d e scribed hereinmay be made to the embodiments lof this invention without'departing fromthe inventive concept.

It is intended that the invention embrace all equivalents within thescope of the appended claims.

We claim:

1. A method of treating a eld with a petroleum based Y Y 25 emulsionmulch comprising the steps `of establishing a movable supply of apetroleum based emulsion vhaving a viscosity of 'between' l0 and-200 SSFat 77 F.moving said supply over a seed 'bed in a field, increasing thepressure on said emulsion to a value of between 30 and 60 p.s.i., owinga portion of saidY emulsion to a position between aboutv 4 and 8 inchesabove the surface of the field, directing a portion of emulsion fromsaid position in a stream of substantially constant density at the seedbed in said iield to produce a spot of emulsiononY the seed bed in saidfield having a diameter of about 2 to 3 inches and continuing to movesaid supply over said lield while periodically directingV additionalportions of theV emulsion from said position at the seedbed in saidfieldV to produce spots of emulsion at, predetermined intervals on theseed bed in thelield.

2. The method of claim 1 further characterized in that the emulsion isan asphalt emulsion.

3. The method of claim 1 further characterized in that D the emulsion isa polybutene emulsion.

References Cited UNITED STATES PATENTS 2,909,869 10/1959 Dresser et ai.47-58 6o 3,061,974 11/1962 Louis etai. 47-9 3,261,127 7/1966 Ferm et ai.47-58 FOREIGN PATENTS Y 205,273 9/1959 Austria. 55 212,372 1/1958Australia.

' ABRAHAM G. STONE, Primary Exaniner.-

R. E. BAGWILL, Asss'tnt Examiner.

1. A METHOD OF TREATING A FIELD WITH A PERTROLEUM BASED EMULSION MULCHCOMPRISING THE STEPS OF ESTABLISHING A MOABLE SUPPLY OF A PETROLEUMBASED EMULSION HAVING A VISCOSITY OF BETWEEN 10 AND 200 SSF AT 77*F.,MOVING SAID SUPPLY OVER A SEED BED IN A FIELD, INCREASING THE PRESSUREON SAID EMULSION TO A VALUE OF BETWEEN 30 AND 60 P.S.I., FLOWING APORTION OF SAID EMULSION TO A POSITION BETWEEN ABOUT 4 AND 8 INCHESABOVE THE SURFACE OF THE FIELD, DIRECTING A PORTION OF EMULSION FROMSAID POSITION IN A STREAM OF SUBSTANTIALLY CONSTANT DENSITY AT THE SEEDBED IN SAID FIRST TO PRODUCE A SPOT OF EMULSION ON THE SEED BED IN SAIDFIELD HAVING A DIAMETER OF ABOUT 2 TO 3 INCHES AND CONTINUING TO MOVESAID SUPPLY OVER SAID FIELD WHILE PERIODICALLY DIRECTING ADDITIONALPORTIONS OF THE EMULSION FROM SAID POSITION AT THE SEED BED IN SAIDFIELD TO PRODUCE SPOTS OF EMULSION AT PREDETERMINED INTERVALS ON THESEED BED IN THE FIELD.